If you want a little one it's from the old UMPC market. I have one that runs xp that is smaller than a cell phone.
I have a Samsung tablet with 7" screen Q1, OQO 01+, HTC Shift x9500 and a few others. On the U810 it is also known as the u1010, there are a few more varations of it as well. In the life book line if you want one a little bigger I think they have ones in a 10" screen and a 12" screen that are dual core.
Here are a few of the ones I am talking about, some I see the prices have gone way up since I snagged mine. http://www.ebay.com/itm/Fujitsu-LifeBoo ... 33a7ee118b
Here is a little one with a 8.9 inch screen, touch, slim and dual core. Haven't had one yet. http://www.ebay.com/itm/Fujitsu-P1630-2 ... 2c9fd50068
there are others in the lifebook like like it.http://www.ebay.com/itm/Sony-VAIO-VGN-U ... 419bbc085dhttp://www.ebay.com/itm/Sony-VAIO-UX380 ... 35f05fab45
The sony ux series were all core solo from the factory but a group on a forum did make a few core 2 duo by doing a CPU swap. Yes it required a hot air machine.http://www.ebay.com/itm/HTC-Shift-X9500 ... 4d2c39bb2e
I have this one, battery life sucks, dual OS one is stuck in italian haven't gotten it running. Runs better with 7, but I need to get back to that one and see why the wifi isn't working anymore on it. The keyboard slides out and then it folds open to hold the screen up.http://www.ebay.com/itm/ITRONIX-IX750-G ... 28065ab51e
I haven't seen one of these on the bay in a while. Always wanted one, but parts are hard to find. Since I got a U1 I kind of forgot about it. They used another brands motherboard to make it, don't remember right off hand, but it was a UMPC.http://www.ebay.com/itm/Rare-Sony-VAIO- ... 2a572b67f8
can't leave the toughbook outhttp://www.ebay.com/itm/Panasonic-Tough ... 25ab1bf369http://www.ebay.com/itm/LIFEBOOK-LOOX-U ... 463f8343b6http://www.ebay.com/itm/MINI-ORDINATEUR ... 419b68b51b
This is one of the smallest you can get. My note 2 phone is bigger, but the OQO is thicker.http://www.ebay.com/itm/OQO-Model-02-5- ... 2a53a659dahttp://www.ebay.com/itm/OQO-Model-02-5- ... 2ee576ac6c
On the samsung Q1 I do like it. I have two. One I coudln't get back working was a older style, and the best one is the "ultra" version. The ultra has a full keyboard as well. They can be had complete for under 100 dollars. http://www.ebay.com/itm/SAMSUNG-Q1-ULTR ... 3ab09616echttp://www.ebay.com/itm/Samsung-Q-1-Ult ... 35ed0c2bdfhttp://www.ebay.com/itm/Ultra-Mobile-PC ... 35f080be57
My ultra has windows 7 on it now, 7" screen. These are still a good deal. There are several different varations, cpu speeds, etc so look them over good before purchase.http://www.ebay.com/itm/BenQ-S6-2GB-Wi- ... 463778db1e
The benq s6 came in linux and xp flavors. SD card for expansion. It ran well. But was replaced with the Samsung. Jeff has it now, not sure what he is doing with it if he still has it.http://www.ebay.com/itm/Viliv-X70-EX-7- ... 235787469bhttp://www.ebay.com/itm/viliv-S5-32GB-S ... 3aafe8718b
Another option is one of thesehttp://www.ebay.com/itm/Craig-7-inch-Wi ... 3f52316805
Straight from the land of knock offs a 5 or 7" laptop running android. That is a older one running android 2.2, there are newer ones.http://www.ebay.com/itm/7-VIA8880-Mini- ... 43e18d08b2